#define _CRT_SECURE_NO_WARNINGS 
#include<stdio.h>
#include<windows.h>
int main()
{
	/*int n = 0;
	while (scanf("%d", &n))
	{
		int i = 0;
		for (i = 0; i < n ; i++)
		{
			int j = 0;
			for (j = 0; j < n ; j++)
			{
				if (i == j || i + j == n - 1 )
				{
					printf("*");
				}
				else
				{
					printf(" ");
				}
			}
			printf("\n");
		}
	}*/
	/*int numbers[10];
	int max_value;
	int i;
	for (i = 0; i < 10; i++)
	{
		scanf("%d",&numbers[i]);
	}
	max_value = numbers[0];
	for(i = 1;i <= 10;i++)
	{
		if (numbers[i] >= max_value)
		{
			max_value = numbers[i];
			//printf("%d ", i);
		}
	}
	while (max_value)
	{
		int a = max_value--;
		printf("%d ", a);
	}
	//printf("The maximum value is : %d\n", max_value);*/
	/*char arr1[] = "welcome to bite";
	char arr2[] = "###############";
	int left = 0;
	int right = sizeof(arr1) / sizeof(arr1[0]) - 2;
	while (left <= right)
	{
		arr2[left] = arr1[left];
		arr2[right] = arr1[right];
		printf("%s\n", arr2);
		Sleep(1000);
		left++;
		right--;
	}*/
	int arr[10] = { 0 };
	int sum = 0;
	for (int i = 0; i < 10; i++)
	{
		scanf("%d", &arr[i]);
	}
	for (int i = 0; i < 10; i++)
	{
		sum += arr[i];
	}
	float a = sum / 10.0;
	printf("%f", a);
	/*int a = 0;
	int n = 0;
	while (scanf("%d", &n) != EOF)
	{
		do
		{
			int i = 0;
			if (i < n - 1)
			{
				printf("  ");
				i++;
			}
			else if (i == n - 1)
			{
				printf("* ");
			}
			a = n--;
		} while (a);
	}*/
	return 0;
}
